JP2023177897A - Multilayer body and container - Google Patents

Abstract

To provide a multilayer body which exhibits good oxygen barrier performance, has a good hue after oxygen absorption and is excellent in strength/shape maintenance, and has good appearance, and a container.SOLUTION: A multilayer body contains at least three layers that layers (B) containing a thermoplastic resin (b) different from a polyester compound (a) are stacked on both sides of a layer (A) containing a resin composition containing the polyester compound (a) containing constitutional units of a 2,6-naphthalene dicarboxylic acid derivative, a tetralin-2,6-dicarboxylic acid derivative and an isophthalic acid derivative, and a transition metal catalyst.SELECTED DRAWING: None

Description

The present invention relates to a multilayer body and a container containing the multilayer body.

To prevent oxygen oxidation of various products such as foods, beverages, pharmaceuticals, and cosmetics that are susceptible to deterioration or deterioration due to the influence of oxygen, and to preserve them for long periods of time, we remove oxygen from the packaging that contains these products. Oxygen absorbers are used.

As the oxygen absorbent, an oxygen absorbent containing iron powder as a main reaction agent is generally used from the viewpoint of oxygen absorption capacity, ease of handling, and safety. However, since this iron-based oxygen absorbent is sensitive to metal detectors, it has been difficult to use metal detectors for foreign object inspection. Furthermore, a package enclosing an iron-based oxygen absorber cannot be heated in a microwave oven due to the risk of ignition. Furthermore, since moisture is essential for the oxidation reaction of iron powder, the oxygen absorption effect could only be achieved if the object to be preserved had a high moisture content.

In addition, by constructing the container using a multilayer material with an oxygen-absorbing layer made of an oxygen-absorbing resin composition containing thermoplastic resin and an iron-based oxygen absorber, we aim to improve the gas barrier properties of the container and improve the effectiveness of the container itself. BACKGROUND ART A packaging container with an oxygen absorption function is being developed (see Patent Document 1). However, this method also has the same problems, such as being sensitive to metal detectors and therefore not being able to be used for that purpose, not being able to be heated in a microwave oven, and being effective only for high-moisture materials. Furthermore, there is a problem of insufficient internal visibility due to the problem of opacity.

Due to the above-mentioned circumstances, an oxygen absorbent having an organic substance as the main reaction agent is desired. As an oxygen absorbent using an organic substance as a main reaction agent, an oxygen absorbent using ascorbic acid as a main agent is known (see Patent Document 2).

On the other hand, oxygen-absorbing resin compositions that are composed of a resin and a transition metal catalyst and have oxygen-scavenging properties are known. For example, a resin composition comprising polyamide, particularly xylylene group-containing polyamide, and a transition metal catalyst as an oxidizing organic component is known (see Patent Document 3). Furthermore, this Patent Document 3 also exemplifies oxygen absorbers, packaging materials, and multilayer laminated films for packaging obtained by molding this resin composition.

Furthermore, as an oxygen-absorbing resin composition that does not require moisture for oxygen absorption, an oxygen-absorbing resin composition consisting of a resin having a carbon-carbon unsaturated bond and a transition metal catalyst is known (see Patent Document 4). .

Further, as a composition for scavenging oxygen, a composition comprising a transition metal and a polymer containing a substituted cyclohexene functional group or a low molecular weight substance to which the cyclohexene ring is bonded is known (see Patent Document 5).

The applicant has proposed an oxygen-absorbing resin composition having a tetralin ring (see Patent Document 6).

Japanese Patent Application Publication No. 09-234832 Japanese Unexamined Patent Publication No. 51-136845 Japanese Patent Application Publication No. 2001-252560 Japanese Patent Application Publication No. 05-115776 Special Publication No. 2003-521552 Patent No. 6124114

However, the oxygen absorbent of Patent Document 2 has the problems that its oxygen absorption performance is low to begin with, that it is effective only when the object to be preserved is a high moisture type, and that it is relatively expensive.

In addition, the resin composition of Patent Document 3 expresses an oxygen absorption function by containing a transition metal catalyst and oxidizing the xylylene group-containing polyamide resin, so that after oxygen absorption, the polymer chain is degraded due to oxidative deterioration of the resin. There is a problem in that cutting occurs and the strength of the packaging container itself is reduced. Furthermore, this resin composition has the problem that its oxygen absorption performance is still insufficient, and the effect is only exhibited when the preserved material is of high moisture content.

Furthermore, in the oxygen-absorbing resin composition of Patent Document 4, low-molecular-weight organic compounds that become odor components are generated due to cleavage of polymer chains accompanying oxidation of the resin, and odor is generated after oxygen absorption. There's a problem.

On the other hand, the composition of Patent Document 5 still has the problem that it is necessary to use a special material containing a cyclohexene functional group, and that this material is relatively likely to generate odor.

The oxygen-absorbing resin composition having a tetralin ring disclosed in Patent Document 6 does not generate any odor after absorbing oxygen and has excellent oxygen-absorbing performance under a wide range of humidity conditions from low humidity to high humidity. There is a problem that it turns yellow and its appearance deteriorates when used as a packaging material.

An object of the present invention is to provide a multilayer body and a container that exhibit good oxygen barrier performance, have a good color tone after oxygen absorption, have excellent strength and shape retention, and have a good appearance.

As a result of intensive studies on multilayer bodies, the present inventors found that a layer (A) containing a resin composition containing a polyester compound (a) having a predetermined structure and a transition metal catalyst, and a layer (A) containing a resin composition containing a polyester compound (a) having a predetermined structure and a transition metal catalyst; It has been discovered that the above problem can be solved by a multilayer body containing at least three layers, in which a layer (B) containing a thermoplastic resin (b) different from a) is laminated on both sides of the layer (A), and the present invention Completed the invention.

That is, the present invention includes the following aspects.
[1] A layer (A) containing a resin composition containing a polyester compound (a) and a transition metal catalyst, and a layer (B) containing a thermoplastic resin (b) different from the polyester compound (a). ) is laminated on both sides of the layer (A), the polyester compound (a) is a multilayer body containing at least three layers laminated on both sides of the layer (A), wherein the polyester compound (a) has the following formula (1) or formula (2) in the polyester compound (a). With respect to a total of 100 mol% of the structural units represented by formula (3), 30 to 55 mol% of the structural unit represented by the following formula (1), and the structural unit represented by the following formula (2). A multilayer body containing 15 to 40 mol% and 20 to 40 mol% of a structural unit represented by the following formula (3).

(In the above formulas (1) to (3), n represents the amount of repeating unit, and the structural unit represented by the above formula (1), the structural unit shown by the above formula (2), and the above formula ( (corresponds to the composition ratio of the structural units expressed in 3)).

[2] The polyester compound (a) has the formula (1) based on the total 100 mol% of the structural units represented by (i) the formula (1), the formula (2), and the formula (3). Contains 40 to 50 mol% of the structural unit represented by the formula (2), 20 to 35 mol% of the structural unit represented by the formula (3), and 25 to 35 mol% of the structural unit represented by the formula (3), and (ii) the total of the structural units represented by formulas (1) to (3) is 95 mol% or more with respect to 100 mol% of all structural units of the polyester compound (a), [1] The multilayer body described in .

[3] The multilayer body according to [1], wherein the transition metal catalyst contains at least one transition metal selected from the group consisting of cobalt, nickel, and copper.

[4] The multilayer body according to [3], wherein the transition metal catalyst is contained in an amount of 0.5 to 10 ppm as a transition metal amount based on the mass of the polyester compound (a).

[5] A container comprising the multilayer body according to any one of [1] to [4].

According to the present invention, it is possible to provide a multilayer body and a container that exhibit good oxygen barrier performance, have a good color tone after oxygen absorption, have excellent strength and shape retention, and have a good appearance.

Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described. Note that this embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. Furthermore, in this specification, "~" is used to include the numerical values described before and after it as a lower limit value and an upper limit value.

[Multilayer body]
The multilayer body of the present embodiment includes a layer (A) (hereinafter also referred to as "layer A") containing a resin composition containing at least a polyester compound (a) and a transition metal catalyst, and a layer (A) containing a resin composition containing at least a polyester compound (a) and a transition metal catalyst. ) containing at least three layers (hereinafter also referred to as "layer B") containing a thermoplastic resin (b) different from the above layer A, the polyester compound (a) , the structural unit represented by the following formula (1) is added to the total of 100 mol% of the structural units represented by the following formula (1), formula (2) and formula (3) in the polyester compound (a). 30 to 55 mol%, 15 to 40 mol% of the structural unit represented by the following formula (2), and 20 to 40 mol% of the structural unit represented by the following formula (3).

(In the above formulas (1) to (3), n represents the amount of repeating unit, and the structural unit represented by the above formula (1), the structural unit shown by the above formula (2), and the above formula ( (corresponds to the composition ratio of the structural units expressed in 3)).

The multilayer body and container according to this embodiment exhibit good oxygen barrier performance, have a good color tone after oxygen absorption, have excellent strength and shape retention, and have a good appearance.
The multilayer body and container according to the present embodiment preferably have excellent oxygen absorption performance under a wide range of humidity conditions from low humidity to high humidity, and absorb oxygen regardless of the presence or absence of moisture in the object to be stored. Moreover, it does not cause odor generation or yellowing after absorbing oxygen, so it can be used in a wide range of applications, such as food, cooked foods, beverages, pharmaceuticals, health foods, etc. . Further, according to a preferred aspect of this embodiment that does not contain iron powder or the like, it is also possible to realize a multilayer body and a container that are not sensitive to metal detectors. Further, according to a preferred aspect of the present embodiment, it is possible to realize a multilayer body and a container in which the decrease in strength after oxygen absorption is extremely small, the strength is maintained even during long-term use, and delamination is less likely to occur.

The multilayer body and container of this embodiment have at least three layers: layer A and layer B laminated on both sides of layer A. The multilayer body and container of this embodiment only need to have a layer B/layer A/layer B structure as the layer structure, and any other layer may be provided. Further, in this specification, the layers B stacked on both sides of the layer A may be the same layer or different layers. Further, the number and type of the multilayer body and container are not particularly limited as long as they include one or more layers of layer A and two or more layers of layer B. For example, it may have a five-layer structure of B1/B2/A/B2/B1, which includes one layer A and four layers B of two types, layer B1 and layer B2. In this specification, both layers B1 may have the same composition or different compositions, and both layer B2 may have the same composition or different compositions. Furthermore, the multilayer body and container of this embodiment may include any layer such as an adhesive layer (layer AD) between layer A and layer B, for example, B1/AD/B2/A A seven-layer structure of /B2/AD/B1 may be used. In this specification, both layers B1 may have the same composition or different compositions, both layers B2 may have the same composition or different compositions, and both layers AD may have the same composition. may be different. In addition, in the multilayer body and container of this embodiment, when it has multiple layers B, it may have layer A between the layers B.

Layer B is laminated on both sides of layer A and layer A because it is easier to mold, has a better color tone after oxygen absorption, and can provide a multilayer injection molded article and container with a better appearance. A three-layer structure of B/A/B is preferable.

The multilayer injection molded body and container are suitable for medical use because the multilayer injection molded body and container have a better color tone after oxygen absorption and a better appearance.

[Layer (A) containing resin composition]
The layer (A) containing the resin composition of the present embodiment contains a polyester compound (a) and a transition metal catalyst, and the polyester compound (a) accounts for all the constituent units of the polyester compound (a). Based on the total number of moles, 35 to 55 mol% of the structural unit represented by the above formula (1), 15 to 40 mol% of the structural unit represented by the above formula (2), and 15 to 40 mol% of the structural unit represented by the above formula (3). Contains 20 to 40 mol% of structural units.

The thickness of layer A is not particularly limited, but is preferably 10 to 1000 μm, more preferably 50 to 700 μm, and even more preferably 100 to 500 μm. By setting it as this range, it tends to be possible to further improve the oxygen barrier performance of layer A and to prevent economic efficiency from being impaired.

<Polyester compound>
The polyester compound (a) of the present embodiment contains structural units represented by the above formulas (1) to (3). Here, "containing a structural unit" means having one or more such structural units in the compound. The above-mentioned structural unit may be either a random copolymer of the above-mentioned structural unit and other structural units, or a block copolymer of the above-mentioned structural unit.

The polyester compound (a) has the formula (1) with respect to the total 100 mol% of the structural units represented by the formula (1), formula (2), and formula (3) in the polyester compound (a). Contains 30 to 55 mol% of the structural units represented by the above formula (2), 15 to 40 mol% of the structural units represented by the above formula (3), and 20 to 40 mol% of the structural units represented by the above formula (3). do. By setting it within the above range, it is possible to have excellent oxygen barrier performance and suppress deterioration of appearance due to yellowing. In particular, if the content of the structural unit of formula (1) is less than 30 mol %, the oxygen barrier properties of the polyester compound (a) will decrease. Moreover, when the structural unit of the above formula (1) exceeds 55 mol%, the oxygen absorption performance of the polyester compound decreases. Furthermore, if the content of the structural unit of the above formula (2) is less than 15 mol %, the oxygen absorption performance of the polyester compound (a) decreases. If the content of the structural unit of formula (2) exceeds 40 mol%, deterioration of appearance due to yellowing will be accelerated. Furthermore, if the content of the structural unit of formula (3) is less than 20 mol %, the oxygen barrier properties of the polyester compound (a) will decrease. Furthermore, if the content of the structural unit of formula (3) exceeds 40 mol %, the amount of low molecular weight components will increase, causing bleeding and mold deposits during molding. From the same viewpoint as above, the polyester compound (a) has a content of (i) a total of 100 mol% of the structural units represented by the above formulas (1), (2), and (3) in the polyester compound (a). On the other hand, 40 to 50 mol% of the structural unit represented by the above formula (1), 20 to 35 mol% of the structural unit represented by the above formula (2), and the structural unit represented by the above formula (3) 25 to 35 mol%, and (ii) the total of the structural units represented by the formulas (1) to (3) based on 100 mol% of the total structural units of the polyester compound (a). is preferably 95 mol% or more.
The content of the structural units represented by formulas (1) to (3) can be determined from the amount charged, or can be measured by ¹ H-NMR in deuterated chloroform.

The method for producing the polyester compound (a) containing the structural units represented by formulas (1) to (3) above in this embodiment is not particularly limited, and any conventionally known method for producing polyester can be applied. can. Examples of methods for producing polyester include melt polymerization methods such as transesterification and direct esterification, and solution polymerization. Among these, the transesterification method or the direct esterification method is preferred from the viewpoint of easy availability of raw materials, in which 2,6-naphthalene dicarboxylic acid or its derivative (I) and 2,6-tetraline dicarboxylic acid or It can be obtained by polycondensing its derivative (II), isophthalic acid or its derivative (III), and ethylene glycol or its derivative (IV).

Various catalysts such as transesterification catalysts, esterification catalysts, and polycondensation catalysts, various stabilizers such as etherification inhibitors, heat stabilizers, and light stabilizers, and polymerization modifiers used in the production of polyester compound (a) are also conventionally known. Any of these can be used, and these are appropriately selected depending on the reaction rate, color tone of the polyester compound, safety, thermal stability, weather resistance, dissolution properties of the polyester compound, etc. For example, the various catalysts mentioned above include compounds of metals such as zinc, lead, cerium, cadmium, cobalt, lithium, sodium, potassium, calcium, nickel, magnesium, vanadium, aluminum, titanium, tin (e.g. fatty acid salts, carbonates, Examples include phosphates, hydroxides, chlorides, oxides, alkoxides) and metal magnesium, and these can be used alone or in combination.

The intrinsic viscosity of the polyester compound of this embodiment (a value measured at 25°C using a mixed solvent of phenol and 1,1,2,2-tetrachloroethane in a mass ratio of 6:4) is not particularly limited, but the polyester compound In terms of moldability, 0.5 to 1.5 dL/g is preferable, and 0.8 to 1.2 dL/g is more preferable.

The polyester compound (a) may contain any structural units other than the structural units represented by the above formulas (1) to (3). Specific examples of such arbitrary structural units include, but are not limited to, units derived from dicarboxylic acids or derivatives thereof and diols or derivatives thereof other than the units described above. The content of arbitrary structural units in the polyester compound (a) is not particularly limited, but is preferably less than 5 mol% with respect to 100 mol% of all structural units of the polyester compound (a).

Diols or derivatives thereof as arbitrary structural units include, but are not limited to, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexane. Diols, aliphatic diols such as neopentyl glycol; 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,2-decahydronaphthalene dimethanol, 1,3-decahydronaphthalene dimethanol, 1, Alicyclic diols such as 4-decahydronaphthalene dimethanol, 1,5-decahydronaphthalene dimethanol, 1,6-decahydronaphthalene dimethanol, 2,7-decahydronaphthalene dimethanol, tetralin dimethanol, or These derivatives can be mentioned. The above diols or derivatives thereof can be used alone or in combination of two or more.

Examples of dicarboxylic acids or derivatives thereof as arbitrary structural units include, but are not limited to, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, aliphatic dicarboxylic acids such as dodecanedioic acid, phthalic acid, Examples include benzenedicarboxylic acids such as terephthalic acid, naphthalene dicarboxylic acids such as 1,5-naphthalene dicarboxylic acid and 2,7-naphthalene dicarboxylic acid, and derivatives thereof. One kind of dicarboxylic acid or its derivative can be used alone or two or more kinds can be used in combination.

<Transition metal catalyst>
The transition metal catalyst used in the resin composition and layer A of the present embodiment can be appropriately selected from known catalysts as long as it can function as a catalyst for the oxidation reaction of the polyester compound. Oxygen barrier properties can be improved through oxygen absorption by the oxidation reaction of the polyester compound. Although not particularly limited, the transition metal contained in the transition metal catalyst is preferably a metal from groups 4 and 8 to 11 of the periodic table. In order to exhibit the effect with a small amount, metals from groups 8 to 11 of the periodic table are more preferable.

Specific examples of such transition metal catalysts include organic acid salts, halides, phosphates, phosphites, hypophosphites, nitrates, sulfates, oxides, and hydroxides of transition metals. Here, examples of the transition metal contained in the transition metal catalyst include, but are not limited to, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, and rhodium. One type of transition metal can be used alone or two or more types can be used in combination. Among these, the transition metal catalyst preferably contains at least one transition metal selected from the group consisting of cobalt, nickel, and copper. Examples of organic acids include acetic acid, propionic acid, octanoic acid, lauric acid, stearic acid, acetylacetone, dimethyldithiocarbamic acid, palmitic acid, 2-ethylhexanoic acid, neodecanoic acid, linoleic acid, tolic acid, oleic acid, Examples include, but are not limited to, capric acid and naphthenic acid. The transition metal catalyst is preferably a combination of these transition metals and an organic acid, where the transition metal is cobalt, nickel or copper, and the organic acid is acetic acid, stearic acid, 2-ethylhexanoic acid, oleic acid or naphthenic acid. More preferred is a combination. Note that the transition metal catalyst can be used alone or in combination of two or more.

The blending amount of the transition metal catalyst can be appropriately set depending on the type of the polyester compound and transition metal catalyst used and the desired performance, and is not particularly limited. From the viewpoint of the oxygen absorption amount and appearance of the resin composition and layer A, the blending amount of the transition metal catalyst is based on the mass of the polyester compound (a), and the transition metal (preferably a metal from Groups 8 to 11 of the periodic table, More preferably cobalt, nickel or copper) is contained in an amount of 0.5 to 10 ppm, more preferably 1 to 5 ppm, and most preferably is 1.5 to 3 ppm. Note that when a transition metal catalyst is used in the production of the polyester compound and remains in the resin composition, the amount of the transition metal contained in the remaining catalyst is also included in the above numerical range. The amount and type of transition metal can be determined by inductively coupled plasma mass spectrometry.

When the amount of transition metal is 0.5 ppm or more, oxygen absorption performance tends to be further improved. When the amount of transition metal is 10 ppm or less, yellowing tends to be further suppressed.

The polyester compound (a) and the transition metal catalyst can be mixed by a known method, but preferably by kneading with an extruder, it can be used as a resin composition with good dispersibility. In addition, the resin composition may contain additives such as desiccants, pigments, dyes, antioxidants, slip agents, antistatic agents, stabilizers, calcium carbonate, clay, mica, etc., to the extent that the effects of this embodiment are not impaired. , fillers such as silica, deodorants, etc. may be added, but the material is not limited to those shown above, and various materials can be mixed.

Note that the resin composition and layer A of the present embodiment may further contain a radical generator or a photoinitiator, if necessary, in order to promote the oxygen absorption reaction. Specific examples of radical generators include various N-hydroxyimide compounds, such as N-hydroxysuccinimide, N-hydroxymaleimide, N,N'-dihydroxycyclohexanetetracarboxylic acid diimide, N-hydroxyphthalimide, N-hydroxytetrachlorophthalimide, N-hydroxytetrabromophthalimide, N-hydroxyhexahydrophthalimide, 3-sulfonyl-N-hydroxyphthalimide, 3-methoxycarbonyl-N-hydroxyphthalimide, 3-methyl-N-hydroxyphthalimide, 3 -Hydroxy-N-hydroxyphthalimide, 4-nitro-N-hydroxyphthalimide, 4-chloro-N-hydroxyphthalimide, 4-methoxy-N-hydroxyphthalimide, 4-dimethylamino-N-hydroxyphthalimide, 4-carboxy-N -Hydroxyhexahydrophthalimide, 4-methyl-N-hydroxyhexahydrophthalimide, N-hydroxyhettyl imide, N-hydroxyhimic acid imide, N-hydroxytrimellitic acid imide, N,N-dihydroxypyromellitic acid diimide, etc. Examples include, but are not particularly limited to. Further, specific examples of photoinitiators include benzophenone and its derivatives, thiazine dyes, metal porphyrin derivatives, anthraquinone derivatives, etc., but are not particularly limited thereto. In addition, these radical generators and photoinitiators can be used individually or in combination of two or more types.

Moreover, the resin composition and layer A of this embodiment may contain thermoplastic resins other than the polyester compound (a) within a range that does not impede the purpose of this embodiment. Further, the resin composition and layer A can be used by being kneaded with other thermoplastic resins in an extruder as long as the purpose of the present embodiment is not impaired. Examples of thermoplastic resins include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, linear very low density polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene. or polyolefins such as random or block copolymers of α-olefins such as ethylene, propylene, 1-butene, and 4-methyl-1-pentene, acid-modified polyolefins such as maleic anhydride grafted polyethylene and maleic anhydride grafted polypropylene. , ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-vinyl chloride copolymer, ethylene-(meth)acrylic acid copolymer and its ionic crosslinked product (ionomer), ethylene-methyl methacrylate copolymer ethylene-vinyl compound copolymers such as polymers, styrenic resins such as polystyrene, acrylonitrile-styrene copolymers, α-methylstyrene-styrene copolymers, polyvinyl compounds such as polymethyl acrylate, polymethyl methacrylate, Polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, polymethaxylylene adipamide (MXD6), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate ( PEN), glycol-modified polyethylene terephthalate (PETG), polyethylene succinate (PES), polybutylene succinate (PBS), polyesters such as polylactic acid, polyglycolic acid, polycaprolactone, polyhydroxyalkanoate, polycarbonate, polyethylene oxide, etc. Examples include polyether and mixtures thereof. Among these, resins with high oxygen barrier properties such as polyester, polyamide, and ethylene-vinyl alcohol copolymers are more preferred in order to effectively exhibit oxygen barrier properties. In addition, when the layer (A) contains the polyolefin mentioned above, it can be distinguished from the layer (B) mentioned later by whether or not it contains the polyester compound (a).

[Layer (B) containing thermoplastic resin (b)]
Layer B of this embodiment contains thermoplastic resin (b). The thermoplastic resin (b) is not particularly limited as long as it is different from the polyester compound (a). The content of the thermoplastic resin (b) in layer B is not particularly limited, but the content of the thermoplastic resin (b) with respect to the total amount of layer B is preferably 70 to 100% by mass, and 80 to 100% by mass. is more preferable, and even more preferably 90 to 100% by mass. By setting it as the said range, the transparency and moldability of layer B can be improved. The thermoplastic resin (b) can be used alone or in combination of two or more.

The multilayer body and container of this embodiment have a multilayer structure in which layers B are laminated on both sides of layer A, and the configurations of the layers B laminated on both sides of layer A may be the same or different. The thickness of layer B can be determined as appropriate depending on the application, and is preferably 30 to 1000 μm from the viewpoint of ensuring various physical properties such as strength and flexibility such as drop resistance required for multilayer bodies and containers. , more preferably 50 to 800 μm, still more preferably 100 to 600 μm. In addition, it shows better oxygen barrier performance, has a better color tone after oxygen absorption, has better strength and shape retention, and has a better appearance. is preferably 100 to 300 μm, the thickness of the intermediate layer (layer A) is preferably 200 to 400 μm, and the thickness of the outer container layer (layer B) is preferably 400 to 600 μm.

Any thermoplastic resin can be used as the thermoplastic resin (b) of this embodiment, and is not particularly limited. Examples include polyolefins, polyesters, polyamides, ethylene-vinyl alcohol copolymers, plant-derived resins, and chlorine-based resins. In this embodiment, the thermoplastic resin (b) preferably contains at least one selected from the group consisting of these resins. These resins can be used alone or in combination of two or more.

<Polyolefin>
Specific examples of polyolefins include polyethylene (low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene), polypropylene, polybutene-1, poly-4-methylpentene-1, ethylene and Known copolymers such as copolymers with α-olefins, propylene and α-olefin copolymers, ethylene-α,β-unsaturated carboxylic acid copolymers, ethylene-α,β-unsaturated carboxylic acid ester copolymers, etc. The resins are preferably ring-opening polymers of cycloolefins such as norbornene or tetracyclododecene or derivatives thereof, hydrogenated products thereof, cycloolefins such as norbornene or tetracyclododecene or derivatives thereof, and ethylene or propylene. It is a copolymer resin in which a cyclopentyl residue or a substituted cyclopentyl residue is inserted into the molecular chain by polymerization with Here, cycloolefins include monocyclic and polycyclic ones. Preferred are thermoplastic norbornene resins or thermoplastic tetracyclododecene resins. Examples of thermoplastic norbornene resins include ring-opening polymers of norbornene monomers, hydrogenated products thereof, addition polymers of norbornene monomers, and addition polymers of norbornene monomers and olefins. It will be done. Thermoplastic tetracyclododecene resins include ring-opening polymers of tetracyclododecene monomers, hydrogenated products thereof, addition polymers of tetracyclododecene monomers, and tetracyclododecene monomers. Examples include addition polymers of polymers and olefins. Thermoplastic norbornene resins are described in, for example, JP-A-3-14882, JP-A-3-122137, and JP-A-4-63807. One kind of polyolefin can be used alone or two or more kinds can be used in combination.

As polyolefins, norbornene, ethylene, etc. can be obtained because they exhibit better oxygen barrier performance, have better color tone after oxygen absorption, are superior in strength and shape retention, and can provide multilayer bodies and containers with better appearance. cycloolefin copolymers (COC), which are copolymers made from olefins such as tetracyclododecene and ethylene, and polymers obtained by ring-opening polymerization and hydrogenation of norbornene. Also preferred are cycloolefin polymers (COP). Such COCs and COPs are described in, for example, Japanese Patent Laid-Open No. 5-300939 or Japanese Patent Laid-Open No. 5-317411.

COC is, for example, manufactured by Mitsui Chemicals Co., Ltd. and is commercially available as APEL (registered trademark), and COP is, for example, manufactured by Nippon Zeon Co., Ltd., as ZEONEX (registered trademark) or ZEONOR (registered trademark), or Daikyo Co., Ltd. It is manufactured by Seiko and is commercially available as Daikyo Resin CZ (registered trademark). Examples of ZEONEX (registered trademark) manufactured by Zeon Corporation include ZEONEX (registered trademark) 690R (trade name).

COC and COP exhibit better oxygen barrier performance, have better color tone after oxygen absorption, have better strength and shape retention, and can provide multilayer bodies and containers with better appearance. Chemical properties such as heat resistance and light resistance show the characteristics of a polyolefin resin, while physical properties such as mechanical properties, melting, flow characteristics, and dimensional accuracy show the characteristics of an amorphous resin. , particularly preferred.

<Polyester>
The polyester described here is a polyester that can be used as the thermoplastic resin (b), and is different from the polyester compound (a) of this embodiment. In this embodiment, the polyester is composed of one or more selected from polyhydric carboxylic acids including dicarboxylic acids and ester-forming derivatives thereof, and one or more selected from polyhydric alcohols including glycol. or hydroxycarboxylic acids and their ester-forming derivatives, or cyclic esters. Ethylene terephthalate thermoplastic polyester has ethylene terephthalate units occupying most of the ester repeating units, generally 70 mol% or more, and has a glass transition point (Tg) of 50 to 90°C and a melting point (Tm) of 200 to 275. C. range is preferred. As an ethylene terephthalate-based thermoplastic polyester, polyethylene terephthalate is particularly excellent in terms of pressure resistance, heat resistance, heat pressure resistance, etc., but in addition to ethylene terephthalate units, dibasic acids such as isophthalic acid and naphthalene dicarboxylic acid and diols such as propylene glycol Copolymerized polyesters containing small amounts of ester units consisting of can also be used. One kind of polyester can be used alone or two or more kinds can be used in combination.

Examples of dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 3- Examples include cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, dimer acid, etc. saturated aliphatic dicarboxylic acids or their ester-forming derivatives, unsaturated aliphatic dicarboxylic acids such as fumaric acid, maleic acid, itaconic acid, or their ester-forming derivatives, orthophthalic acid, isophthalic acid, terephthalic acid , 1,3-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, Aromatic dicarboxylic acids exemplified by 4,4'-biphenylsulfone dicarboxylic acid, 4,4'-biphenyl ether dicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, anthracene dicarboxylic acid, etc. or ester-forming derivatives thereof, 5-sodium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 5-lithium sulfoisophthalic acid, 2-lithium sulfoterephthalic acid, 5-potassium sulfoisophthalic acid, 2-potassium sulfoterephthalic acid, etc. Examples include metal sulfonate group-containing aromatic dicarboxylic acids or lower alkyl ester derivatives thereof.

Among the above dicarboxylic acids, terephthalic acid, isophthalic acid, and naphthalene dicarboxylic acid are particularly preferred in terms of the physical properties of the resulting polyester, and other dicarboxylic acids may be copolymerized as necessary. .

Polycarboxylic acids other than these dicarboxylic acids include ethanetricarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, 3,4,3',4'-biphenyltetracarboxylic acid, and ester-forming derivatives thereof.

Glycols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4 -Butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol , 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,10-decamethylene glycol, 1,12-dodecanediol, polyethylene glycol, polytrimethylene glycol, polytetramethylene Aliphatic glycols such as glycols, hydroquinone, 4,4'-dihydroxybisphenol, 1,4-bis(β-hydroxyethoxy)benzene, 1,4-bis(β-hydroxyethoxyphenyl)sulfone, Bis(p-hydroxyphenyl) ether, bis(p-hydroxyphenyl) sulfone, bis(p-hydroxyphenyl)methane, 1,2-bis(p-hydroxyphenyl)ethane, bisphenol A, bisphenol C, 2,5- Examples of aromatic glycols include naphthalene diol and glycols obtained by adding ethylene oxide to these glycols.

Among the above glycols, it is particularly preferable to use ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, and 1,4-cyclohexanedimethanol as the main component. Polyhydric alcohols other than these glycols include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol, hexanetriol, and the like. Examples of hydroxycarboxylic acids include lactic acid, citric acid, malic acid, tartaric acid, hydroxyacetic acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, 4-hydroxycyclohexanecarboxylic acid, or these. Examples include ester-forming derivatives of.

Examples of the cyclic ester include ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolide, and lactide.

Examples of ester-forming derivatives of polyhydric carboxylic acids and hydroxycarboxylic acids include their alkyl esters, acid chlorides, and acid anhydrides.

The polyester used in this embodiment is preferably a polyester whose main acid component is terephthalic acid or its ester-forming derivative or naphthalene dicarboxylic acid or its ester-forming derivative, and whose main glycol component is alkylene glycol.

The polyester whose main acid component is terephthalic acid or its ester-forming derivative is preferably a polyester containing 70 mol% or more of terephthalic acid or its ester-forming derivative based on the total acid component, and more preferably Preferably it is a polyester containing 80 mol% or more, and more preferably a polyester containing 90 mol% or more. Similarly, the polyester whose main acid component is naphthalene dicarboxylic acid or its ester-forming derivative preferably contains 70 mol% or more in total of naphthalene dicarboxylic acid or its ester-forming derivative, more preferably 80 mol% or more. It is a polyester containing mol% or more, more preferably 90 mol% or more.

Examples of naphthalene dicarboxylic acid or its ester-forming derivative used in this embodiment include 1,3-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2 , 6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, or ester-forming derivatives thereof are preferred.

The polyester whose main glycol component is alkylene glycol is preferably a polyester containing 70 mol% or more, more preferably 80 mol% or more of alkylene glycol based on all glycol components, More preferably, it is a polyester containing 90 mol% or more. The alkylene glycol mentioned here may contain a substituent or an alicyclic structure in its molecular chain.

Copolymerization components other than the above terephthalic acid/ethylene glycol include isophthalic acid, 2,6-naphthalene dicarboxylic acid, diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,2-propanediol, 1,3-propane. At least one selected from the group consisting of diol and 2-methyl-1,3-propanediol is preferable in order to achieve both transparency and moldability, and in particular, isophthalic acid, diethylene glycol, neopentyl glycol, More preferably, it is at least one selected from the group consisting of 1,4-cyclohexanedimethanol.

A preferred example of the polyester used in this embodiment is a polyester whose main repeating unit is composed of ethylene terephthalate, more preferably a linear polyester containing 70 mol% or more of ethylene terephthalate units, and even more preferably a linear polyester containing ethylene terephthalate units. A linear polyester containing 80 mol% or more of ethylene terephthalate units is particularly preferred, and a linear polyester containing 90 mol% or more of ethylene terephthalate units is particularly preferred.

Another preferable example of the polyester used in this embodiment is a polyester in which the main repeating unit is composed of ethylene-2,6-naphthalate, more preferably 70 mol% or more of ethylene-2,6-naphthalate units. A linear polyester containing ethylene-2,6-naphthalate units, more preferably a linear polyester containing 80 mol% or more of ethylene-2,6-naphthalate units, particularly preferably a linear polyester containing 90 mol% or more of ethylene-2,6-naphthalate units. Polyester.

Other preferable examples of the polyester used in this embodiment include linear polyester containing 70 mol% or more of propylene terephthalate units, linear polyester containing 70 mol% or more of propylene naphthalate units, and 1,4-cyclohexane dimethylene. A linear polyester containing 70 mol% or more of terephthalate units, a linear polyester containing 70 mol% or more of butylene naphthalate units, or a linear polyester containing 70 mol% or more of butylene terephthalate units.

In particular, as for the overall composition of the polyester, the combination of terephthalic acid/isophthalic acid//ethylene glycol, the combination of terephthalic acid//ethylene glycol/1,4-cyclohexanedimethanol, and the combination of terephthalic acid//ethylene glycol/neopentyl glycol are transparent. This is preferable in terms of achieving both properties and moldability. It goes without saying that a small amount (5 mol % or less) of diethylene glycol produced by dimerization of ethylene glycol may be included during the esterification (transesterification) reaction and polycondensation reaction.

Other preferable examples of the polyester used in this embodiment include polyglycolic acid obtained by polycondensation of glycolic acid or methyl glycolate, or ring-opening polycondensation of glycolide. This polyglycolic acid may be copolymerized with other components such as lactide.

<Polyamide>
The polyamides used in this embodiment include polyamides whose main constituent units are units derived from lactams or aminocarboxylic acids, and aliphatic polyamides whose main constituent units are units derived from aliphatic diamines and aliphatic dicarboxylic acids. Polyamide, partially aromatic polyamide whose main constituent unit is a unit derived from an aliphatic diamine and an aromatic dicarboxylic acid, partially aromatic whose main constituent unit is a unit derived from an aromatic diamine and an aliphatic dicarboxylic acid Examples include polyamide, and if necessary, monomer units other than the main structural units may be copolymerized. One kind of polyamide can be used alone or two or more kinds can be used in combination.

As the lactam or aminocarboxylic acid, lactams such as ε-caprolactam and laurolactam, aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid, aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid, etc. can be used. .

As the aliphatic diamine, an aliphatic diamine having 2 to 12 carbon atoms or a functional derivative thereof can be used. Furthermore, an alicyclic diamine may be used. The aliphatic diamine may be a linear aliphatic diamine or a branched chain aliphatic diamine. Specific examples of such linear aliphatic diamines include ethylenediamine, 1-methylethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, Examples include aliphatic diamines such as nonamethylene diamine, decamethylene diamine, undecamethylene diamine, and dodecamethylene diamine. Specific examples of the alicyclic diamine include cyclohexane diamine, 1,3-bis(aminomethyl)cyclohexane, and 1,4-bis(aminomethyl)cyclohexane.

Further, as the aliphatic dicarboxylic acid, linear aliphatic dicarboxylic acids and alicyclic dicarboxylic acids are preferable, and linear aliphatic dicarboxylic acids having an alkylene group having 4 to 12 carbon atoms are particularly preferable. Examples of such linear aliphatic dicarboxylic acids include adipic acid, sebacic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, undecanoic acid, undecadionic acid, dodecanedioic acid, dimer acid and their functional Derivatives etc. can be mentioned. Examples of the alicyclic dicarboxylic acid include alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid.

Further, examples of the aromatic diamine include metaxylylene diamine, para-xylylene diamine, para-bis(2-aminoethyl)benzene, and the like.

Examples of the aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and functional derivatives thereof. It will be done.

Specific polyamides include polyamide 4, polyamide 6, polyamide 10, polyamide 11, polyamide 12, polyamide 4,6, polyamide 6,6, polyamide 6,10, polyamide 6T, polyamide 9T, polyamide 6IT, and polymethaxylylene azide. Pamide (Polyamide MXD6), Isophthalic acid copolymerized polymethaxylylene adipamide (Polyamide MXD6I), Polymethaxylylene sebacamide (Polyamide MXD10), Polymethaxylylene dodecanamide (Polyamide MXD12), Poly 1,3-bis Examples include aminocyclohexane adipamide (polyamide BAC6) and polyparaxylylene sebacamide (polyamide PXD10). More preferred polyamides include polyamide 6, polyamide MXD6, and polyamide MXD6I.

Further, as a copolymerization component of the polyamide, a polyether having a number average molecular weight of 2,000 to 20,000 and having at least one terminal amino group or a terminal carboxyl group, or an organic carboxylate of the polyether having the terminal amino group, or Amino salts of polyethers having the aforementioned terminal carboxyl groups can also be used. A specific example is bis(aminopropyl)poly(ethylene oxide) (polyethylene glycol having a number average molecular weight of 2,000 to 20,000).

Further, the partially aromatic polyamide may contain a substantially linear structural unit derived from a polyhydric carboxylic acid having three or more bases, such as trimellitic acid and pyromellitic acid.

<Ethylene-vinyl alcohol copolymer>
The ethylene-vinyl alcohol copolymer used in this embodiment is not particularly limited, but preferably has an ethylene content of 15 to 60 mol%, more preferably 20 to 55 mol%, and more preferably 29 to 44 mol%. The degree of saponification of the vinyl acetate component is preferably 90 mol% or more, more preferably 95 mol% or more.
In addition, the ethylene-vinyl alcohol copolymer may contain a small amount of propylene, isobutene, α-olefin such as α-octene, α-dodecene, α-octadecene, unsaturated It may also contain comonomers such as carboxylic acids or salts thereof, partial alkyl esters, fully alkyl esters, nitriles, amides, anhydrides, unsaturated sulfonic acids or salts thereof. The ethylene-vinyl alcohol copolymer can be used alone or in combination of two or more.

<Plant-derived resin>
The plant-derived resin used in this embodiment may be any resin that contains a plant-derived substance as a raw material, and the plant-derived substance used as a raw material is not particularly limited. Specific examples include aliphatic polyester biodegradable resins. Examples of aliphatic polyester biodegradable resins include poly(α-hydroxy acids) such as polyglycolic acid (PGA) and polylactic acid (PLA); polybutylene succinate (PBS), polyethylene succinate (PES), etc. Examples include polyalkylene alkanoate. One type of plant-derived resin can be used alone or two or more types can be used in combination.

<Chlorine resin>
The chlorine-based resin used in this embodiment may be any resin containing chlorine in its structural unit, and any known resin may be used. Specific examples include polyvinyl chloride, polyvinylidene chloride, and copolymers of these with vinyl acetate, maleic acid derivatives, higher alkyl vinyl ethers, and the like. One type of chlorine-based resin can be used alone or two or more types can be used in combination.

[Other layers]
In addition to layer A and layer B, the multilayer body and container of this embodiment may include other layers depending on desired performance and the like. The other layers may be the same or different in composition from the layers A and B, as long as they are laminated in such a way that they can be distinguished from the layers A and B in the multilayer body and container. Examples of other layers include an adhesive layer and the like.

In the multilayer body and container of this embodiment, if practical interlayer adhesive strength cannot be obtained between two adjacent layers, it is preferable to provide an adhesive layer (AD) between the two layers. The adhesive layer preferably contains a thermoplastic resin having adhesive properties. Examples of adhesive thermoplastic resins include acid-modified polyolefins obtained by modifying polyolefin resins such as polyethylene or polypropylene with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid. Examples include polyester thermoplastic elastomers whose main components are resins and polyester block copolymers. As the adhesive layer, from the viewpoint of adhesiveness, it is preferable to use a modified resin of the same type as the thermoplastic resin (b) used as layer B. The thickness of the adhesive layer is preferably 2 to 100 μm, more preferably 5 to 90 μm, and still more preferably 10 to 80 μm, from the viewpoint of ensuring moldability while exhibiting practical adhesive strength.

[Method for manufacturing multilayer body]
The manufacturing method and layer structure of the multilayer body of this embodiment are not particularly limited, and may be selected from known methods such as injection molding, coextrusion molding, and compression molding, taking into consideration the structure of the molded product including the multilayer body. A suitable manufacturing method is selected. For example, films and sheets can be formed by coextrusion molding by extruding a melted resin composition through a T-die, circular die, etc. from an extruder. It is also possible to process the obtained film into a stretched film by stretching it. In addition, for a bottle-shaped multilayer body, for example, using a molding machine equipped with two or more injection machines and an injection mold, the material constituting layer A and the material constituting layer B are injected into respective injection cylinders. A multilayer body corresponding to the shape of the injection mold can be manufactured by injecting the resin into the cavity through a mold hot runner.

Also, first, the material constituting layer B is injected from an injection cylinder, then the material constituting layer A is injected from another injection cylinder simultaneously with the resin constituting layer B, and then the resin constituting layer B is injected. By injecting a required amount of the material to fill the cavity, a multilayer body with a three-layer configuration B/A/B can be manufactured.

Also, by first injecting the material constituting layer B, then injecting the material constituting layer A alone, and finally injecting the required amount of material constituting layer B to fill the mold cavity, A multilayer body with a five-layer configuration B/A/B/A/B can be produced.

Also, first, the material constituting layer B1 is injected from an injection cylinder, then the material constituting layer B2 is injected from another injection cylinder simultaneously with the resin constituting layer B1, and then the resin constituting layer A is injected. is simultaneously injected with the resins constituting layers B1 and B2, and then the required amount of resin constituting layer B1 is injected to fill the cavity, thereby creating a multilayer body with a five-layer configuration B1/B2/A/B2/B1. can be manufactured. In order to impart heat resistance to the mouth and neck portion of the obtained molded article, the mouth and neck portion may be crystallized by heat treatment at this stage. The degree of crystallinity is preferably 30-50%, more preferably 35-45%. Note that crystallization may be performed after performing secondary processing, which will be described later.

[container]
The container of this embodiment includes the multilayer body of this embodiment. The container has good oxygen barrier properties, good color tone after oxygen absorption, excellent strength and shape retention, and has a good appearance.
When the multilayer body of this embodiment itself is a container, it has good oxygen barrier properties, good color tone after oxygen absorption, excellent strength and shape retention, and has a good appearance. Furthermore, in addition to the slight amount of oxygen that enters from outside the container, it can also absorb oxygen within the container to prevent the stored contents from deteriorating due to oxygen.

The shapes of the multilayer body and the container of this embodiment are not particularly limited, and can be made into any shape depending on the mold. Considering that the multilayer body of this embodiment can exhibit oxygen barrier performance, the multilayer body and container of this embodiment are preferably storage containers such as cup-shaped containers and bottle-shaped containers. Further, for secondary processing such as blow molding as described below, such as a PET bottle, the multilayer body of this embodiment is preferably a test tube-shaped preform (parison).

The container of this embodiment can also be obtained by further processing (that is, secondary processing) the multilayer body of this embodiment. The container has good oxygen barrier properties, good color tone after oxygen absorption, excellent strength and shape retention, and has a good appearance. Furthermore, in addition to the slight amount of oxygen that enters from outside the container, it can also absorb oxygen within the container to prevent the stored contents from deteriorating due to oxygen. Examples of secondary processing methods include injection blow molding and stretch blow molding. Containers obtained through secondary processing include bottles and vials.

<Injection blow molding>
In injection blow molding, first a test tube-shaped preform (parison) is molded as the multilayer body of this embodiment, then the mouth of the heated preform is fixed with a jig, and the preform is fitted into a final shape mold. By blowing air through the mouth, the preform is inflated and brought into close contact with the mold, and then cooled and solidified to form a bottle shape.

In addition, in injection stretch blow molding, the mouth of a heated preform is fixed with a jig, the preform is fitted into a final shape mold, and air is blown into the preform while stretching it with a stretching rod from the mouth. It can be molded into a bottle by blow-stretching it, bringing it into close contact with a mold, and cooling and solidifying it.
Injection stretch blow molding methods can be broadly classified into hot parison methods and cold parison methods. In the former method, the preform is blow molded in a softened state without being completely cooled. On the other hand, in the latter cold parison method, the preform is formed as a supercooled bottomed preform that is considerably smaller than the dimensions of the final shape and the resin is amorphous, and this preform is preheated to the drawing temperature to form the final shape. It is suitable for mass production because it is stretched in the axial direction in a mold and blow-stretched in the circumferential direction. In either method, this multilayer preform is heated to a stretching temperature higher than the glass transition point (Tg), and then stretched by stretch blow molding in a final shape mold heated to a heat setting temperature. It is stretched in the machine direction and also stretched in the cross direction with blow air. The stretching ratio of the final blow molded product is preferably 1.2 to 6 times in the machine direction and 1.2 to 4.5 times in the transverse direction.

The final shape mold described above is heated to a temperature that promotes crystallization of the resin, for example, 120 to 230 °C for PET resin, preferably 130 to 210 °C, and during blowing, the outside of the vessel wall of the molded body is heated to a temperature that promotes crystallization of the resin. Heat treatment is performed by contacting the inner surface for a predetermined period of time. After heat treatment for a predetermined time, the blowing fluid is switched to an internal cooling fluid to cool the inner layer. The heat treatment time varies depending on the thickness and temperature of the blow molded product, but is generally 1.5 to 30 seconds, preferably 2 to 20 seconds in the case of PET resin. On the other hand, the cooling time also varies depending on the heat treatment temperature and the type of cooling fluid, but is generally 0.1 to 30 seconds, preferably 0.2 to 20 seconds. Through this heat treatment, each part of the molded body is crystallized.

Cooling fluids include air at room temperature, various cooled gases such as -40°C to +10°C nitrogen, air, and carbon dioxide, as well as chemically inert liquefied gases such as liquefied nitrogen gas and liquefied gas. Carbon dioxide gas, liquefied trichlorofluoromethane gas, liquefied dichlorodifluoromethane gas, other liquefied aliphatic hydrocarbon gases, etc. can be used. This cooling fluid may also contain a liquid mist having a large heat of vaporization, such as water. By using the cooling fluids described above, significantly higher cooling temperatures can be obtained. In addition, two molds are used for stretch blow molding, and the first mold is heat-treated within a predetermined temperature and time range, and then the blow molded product is transferred to the second mold for cooling, and then again. The blow molded article may be cooled at the same time as blowing. The outer layer of the blow-molded product taken out from the mold is cooled by standing to cool or by blowing cold air.

<Stretch blow molding>
In the stretch blow molding method, the multilayer preform is made into a primary blow molded body with a size larger than the final blow molded body using a primary stretch blow mold, and then this primary blow molded body is heated and shrunk, and then a second blow molded body is formed. One example is two-stage blow molding in which stretch blow molding is performed using a subsequent mold to obtain a final blow molded product. According to this method for producing a blow molded body, the bottom of the blow molded body is sufficiently thinned by stretching, and a blow molded body with excellent resistance to deformation and impact at the bottom during hot filling and heat sterilization can be obtained. .

[others]
The multilayer body of this embodiment, the container obtained from the multilayer body, and the container obtained by secondary processing of the multilayer body (hereinafter also referred to as "multilayer body, container, etc.") are coated with a vapor-deposited film of an inorganic substance or an inorganic oxide. Alternatively, it may be coated with an amorphous carbon film.

Examples of the inorganic substance or inorganic oxide include aluminum, alumina, and silicon oxide. A vapor-deposited film of an inorganic substance or an inorganic oxide can shield eluates such as acetaldehyde and formaldehyde from a multilayer body, a container, and the like. The method for forming the deposited film is not particularly limited, and examples thereof include physical vapor deposition methods such as vacuum vapor deposition, sputtering, and ion plating, and chemical vapor deposition methods such as PECVD. The thickness of the deposited film is preferably 5 to 500 nm, more preferably 5 to 200 nm, from the viewpoint of gas barrier properties, light shielding properties, bending resistance, etc.

The amorphous carbon film is a diamond-like carbon film, and is a hard carbon film also called an i-carbon film or a hydrogenated amorphous carbon film. As a method for forming the film, a method is exemplified in which the inside of the hollow molded body is evacuated by evacuation, a carbon source gas is supplied thereto, and the carbon source gas is turned into plasma by supplying energy for plasma generation. Thereby, an amorphous carbon film can be formed on the inner surface of the multilayer body, container, etc. The amorphous carbon film can not only significantly reduce the permeability of low-molecular-weight inorganic gases such as oxygen and carbon dioxide, but also suppress the sorption of various low-molecular-weight organic compounds that have odors. The thickness of the amorphous carbon film is preferably 50 to 5000 nm from the viewpoints of suppressing the sorption of low-molecular-weight organic compounds, improving gas barrier properties, adhesion to plastics, durability, transparency, and the like.

The multilayer body, container, etc. exhibit good oxygen barrier performance, have a good color tone after absorbing oxygen, have excellent strength and shape retention, and have a good appearance. Furthermore, since multilayer bodies, containers, etc. do not require moisture for oxygen absorption, they have excellent oxygen absorption performance under a wide range of humidity conditions from low humidity to high humidity, and also have excellent flavor retention of the contents. Therefore, multilayer bodies, containers, etc. are suitable for packaging various articles.

Specific examples of things to be preserved include beverages such as milk, juice, coffee, tea, and alcoholic beverages; liquid seasonings such as sauces, soy sauce, and dressings; cooked foods such as soups, stews, and curries; and jams, mayonnaise, etc. Paste-like foods; Marine products such as tuna and fish and shellfish; Processed milk products such as cheese and butter; Processed meat products such as meat, salami, sausage, and ham; Vegetables such as carrots and potatoes; Eggs; Noodles; Before cooking Processed rice products such as rice, cooked rice, and rice porridge; powdered seasonings, powdered coffee, powdered milk for infants, cooked foods for infants, powdered diet foods, nursing care foods, dried vegetables, dried foods such as rice crackers, etc. Chemicals such as pesticides and insecticides; Pharmaceutical products; Pet food; Detergents, and various other products can be mentioned, but are not particularly limited thereto. In particular, contents that tend to deteriorate in the presence of oxygen, such as beverages such as beer, wine, fruit juice, carbonated soft drinks, etc., and foods such as fruits, nuts, vegetables, meat products, infant foods, coffee, jam, mayonnaise, and ketchup. It is suitable for packaging materials such as edible oils, dressings, sauces, tsukudani, dairy products, and other products such as pharmaceuticals and cosmetics.

Moreover, before and after filling these objects to be preserved, the multilayer body, the container, etc., and the objects to be preserved can be sterilized in a form suitable for the objects to be preserved. Sterilization methods include heat sterilization such as hot water treatment at 100℃ or lower, pressurized hot water treatment at 100℃ or higher, ultra-high temperature heat treatment at 130℃ or higher, electromagnetic wave sterilization such as ultraviolet rays, microwaves, and gamma rays, and ethylene oxide. Examples include gas treatment such as sterilization, sterilization using chemicals such as hydrogen peroxide and hypochlorous acid, etc.

The present embodiment will be described in more detail below using Examples and Comparative Examples, but the present embodiment is not limited thereto.

<Evaluation method of multilayer body>
(1) Oxygen barrier property The oxygen barrier property was evaluated by the oxygen permeability of the vial obtained by the method described below. The oxygen permeability was measured using OX-TRAN2/21 manufactured by MOCON under measurement conditions of 23° C. and 65% RH. A sample whose oxygen permeability was less than 0.0005 cc/package/day, which is the lower detection limit of the device, was judged to have good oxygen barrier properties.

(2) Container color change (ΔYI)
The color change (ΔYI) of the container was determined by using a vial obtained by the method described below, filled with 10 cc of distilled water, and sealed with a rubber stopper and an aluminum seal. It was calculated from the difference between the initial yellowness (YI) measured using a color measuring device COH-300A and the yellowness (YI) after storage for 3 months at 40° C. and 20% RH. When ΔYI did not exceed 2, it was judged that the color tone change was small.

(3) Moldability Moldability was confirmed by visually observing the mold after 1000 shot molding of the vial obtained by the method described below. Those with no adhesion of mold deposits were judged to have passed.

(4) Shape/strength retention Shape/strength retention was determined by storing samples at 40°C, 100% RH, using a vial obtained by the method described below, filled with 10 cc of distilled water, and sealed with a rubber stopper and an aluminum seal. It was stored for 3 months. Thereafter, the vial was disassembled, the intermediate layer (A) was taken out, and the condition of the intermediate layer (A) was visually confirmed. Those in which the shape and strength of the intermediate layer (A) were maintained were considered to be passed.

<Manufacture of vials>
Under the following conditions, a vial having a three-layer structure of layer B/layer A/layer B from the outside was obtained, having an inner volume of 10 cc, an overall height of 45 mm, an outer diameter of 24 mmφ, and a wall thickness of 1 mm, and having a shape according to ISO 8362-1.
Using an injection blow integrated molding machine (manufactured by Nissei ASB Machinery Co., Ltd., model "ASB12N-10T") equipped with two injection cylinders, the material constituting layer B is injected from the injection cylinders, and then the layer The material constituting A is injected simultaneously with the resin constituting layer B from another injection cylinder, and then the required amount of resin constituting layer B is injected to fill the cavity in the injection mold, thereby forming the inner layer of the container. A multilayer body having a three-layer structure of B/A/B was obtained, in which the thickness of (layer B) was 200 μm, the thickness of the intermediate layer (layer A) was 300 μm, and the thickness of the outer layer of the container (layer B) was 500 μm. The obtained multilayer body was cooled to a predetermined temperature, transferred to a blow mold, and then blow molded to produce a vial (bottle part).
In addition, for both the container inner layer and the container outer layer, a cycloolefin polymer (manufactured by Nippon Zeon Co., Ltd., product name: "ZEONEX (registered trademark) 690R") was used as layer B, and layer A of the example and comparative example. A resin composition was used.
(Injection and blow conditions)
Injection cylinder temperature for layer B: 325℃
Injection cylinder temperature for layer A: 220℃
Temperature of resin flow path in injection mold: 285℃
Injection mold temperature: 80℃
Blow mold temperature: 20℃
Primary blow pressure: 1.0MPa
Secondary blow pressure: 3.0MPa

[Production example of polyester compound]
(Manufacturing example 1)
8,668.9 g of dimethyl 2,6-naphthalene dicarboxylate was placed in a 30 L polyester resin manufacturing equipment equipped with a packed column type rectification column, partial condenser, total condenser, cold trap, stirrer, heating device, and nitrogen introduction tube. , 4895.5 g of dimethyl tetralin-2,6-dicarboxylate, 4594.6 g of dimethyl isophthalate, 8811.8 g of ethylene glycol, 0.559 g of potassium titanium oxalate dihydrate, and 1.519 g of zinc acetate were charged, and the mixture was heated in a nitrogen atmosphere. The temperature was raised to 230°C to carry out the transesterification reaction. After the reaction conversion rate of the dicarboxylic acid component was 95% or more, 1039.6 g of germanium oxide 0.5% by mass ethylene glycol solution and 154.6 g of phosphoric acid ethylene glycol solution were added, and the temperature was gradually increased and the pressure was reduced. Polycondensation was carried out at 270° C. and 133 Pa or less, and after reaching a predetermined torque, the product was taken out in the form of a strand from the bottom of the production apparatus and cut with a pelletizer to obtain a polyester compound (1) in the form of pellets. Note that the mol% of the structural units represented by formulas (1) to (3) shown in Table 1 is a value calculated from the amount of the corresponding monomer charged.

(Manufacturing example 2)
A polyester compound was prepared in the same manner as in Production Example 1, except that 6730.6 g of dimethyl 2,6-naphthalene dicarboxylate, 6841.7 g of dimethyl tetralin-2,6-dicarboxylate, 4586.5 g of dimethyl isophthalate, and 8796.2 g of ethylene glycol were used. (2) was obtained.

(Manufacturing example 3)
A polyester compound was prepared in the same manner as in Production Example 1, except that 4025.9 g of dimethyl 2,6-naphthalene dicarboxylate, 6138.6 g of dimethyl tetralin-2,6-dicarboxylate, 8001.6 g of dimethyl isophthalate, and 9207.7 g of ethylene glycol were used. (3) was obtained.

(Manufacturing example 4)
A polyester compound was prepared in the same manner as in Production Example 1, except that 3835.9 g of dimethyl 2,6-naphthalene dicarboxylate, 9748.0 g of dimethyl tetralin-2,6-dicarboxylate, 4574.4 g of dimethyl isophthalate, and 8773.0 g of ethylene glycol were used. (4) was obtained.

(Manufacturing example 5)
A polyester compound was prepared in the same manner as in Production Example 1, except that 11,589.2 g of dimethyl 2,6-naphthalene dicarboxylate, 5,622.9 g of dimethyl tetralin-2,6-dicarboxylate, 1,465.9 g of dimethyl isophthalate, and 8,835.2 g of ethylene glycol were used. (5) was obtained.

(Manufacturing example 6)
A polyester compound (6) was prepared in the same manner as in Production Example 1, except that dimethyl 2,6-naphthalenedicarboxylate and dimethyl isophthalate were not used, and dimethyl tetralin-2,6-dicarboxylate was 18147.3 g and ethylene glycol was 8166.1 g. I got it.

(Example 1)
Cobalt (II) stearate was blended with the polyester compound (1) to give a cobalt content of 2.5 ppm, and the resulting resin composition was passed through a twin-screw extruder having two screws with a diameter of 20 mm. A resin composition (1) in the form of pellets was obtained by extrusion in the form of a strand at an extrusion temperature of 280° C. and a screw rotation speed of 50 rpm, and cut with a pelletizer. Using the obtained resin composition, a multilayer body (1) (vial) is molded by the method described above, and the multilayer body (1) is tested by the method described above for oxygen barrier properties, color change of the container, moldability, and shape.・Evaluation of strength maintenance was conducted. The evaluation results are shown in Table 1.

(Example 2)
A resin composition (2) was obtained in the same manner as in Example 1 except that polyester compound (2) was used instead of polyester compound (1). Using the obtained resin composition, a multilayer body (2) (vial) is molded by the method described above, and the multilayer body (2) is evaluated for oxygen barrier properties, color change of the container, moldability, and shape by the method described above.・Evaluation of strength maintenance was conducted. The evaluation results are shown in Table 1.

(Example 3)
A resin composition (3) was obtained in the same manner as in Example 1, except that cobalt (II) stearate was blended to have a cobalt content of 20 ppm. Using the obtained resin composition, a multilayer body (3) (vial) is molded by the method described above, and the multilayer body (3) is evaluated for oxygen barrier properties, color change of the container, moldability, and shape by the method described above.・Evaluation of strength maintenance was conducted. The evaluation results are shown in Table 1.

(Comparative example 1)
A resin composition (4) was obtained in the same manner as in Example 1 except that polyester compound (3) was used instead of polyester compound (1). Using the obtained resin composition, a multilayer body (4) (vial) is molded by the method described above, and the multilayer body (4) is evaluated for oxygen barrier properties, color change of the container, moldability, and shape by the method described above.・Evaluation of strength maintenance was conducted. The evaluation results are shown in Table 1.

(Comparative example 2)
A resin composition (5) was obtained in the same manner as in Example 1 except that polyester compound (4) was used instead of polyester compound (1). Using the obtained resin composition, a multilayer body (5) (vial) is molded by the method described above, and the multilayer body (5) is evaluated for oxygen barrier properties, color change of the container, moldability, and shape by the method described above.・Evaluation of strength maintenance was conducted. The evaluation results are shown in Table 1.

(Comparative example 3)
A resin composition (6) was obtained in the same manner as in Example 1 except that polyester compound (5) was used instead of polyester compound (1). Using the obtained resin composition, a multilayer body (6) (vial) is molded by the method described above, and the multilayer body (6) is tested for oxygen barrier properties, color change of the container, moldability, and shape by the method described above.・Evaluation of strength maintenance was conducted. The evaluation results are shown in Table 1.

(Comparative example 4)
A resin composition (7) was obtained in the same manner as in Example 1 except that polyester compound (6) was used instead of polyester compound (1). Using the obtained resin composition, a multilayer body (7) (vial) is molded by the method described above, and the multilayer body (7) is tested for oxygen barrier properties, color change of the container, moldability, and shape by the method described above.・Evaluation of strength maintenance was conducted. The evaluation results are shown in Table 1.

(Comparative example 5)
Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: MX Nylon S7007) was used in place of the polyester compound (1), cobalt (II) stearate was blended to a cobalt content of 20 ppm, and a vial was prepared. A resin composition (8) was obtained in the same manner as in Example 1, except that the temperature of the injection cylinder for layer A during production was 260°C. Using the obtained resin composition, a multilayer body (8) (vial) is molded by the method described above, and the multilayer body (8) is tested for oxygen barrier properties, color change of the container, moldability, and shape by the method described above.・Evaluation of strength maintenance was conducted. The evaluation results are shown in Table 1.

As is clear from Examples 1 to 3, it was confirmed that the multilayer body of the present invention exhibited good oxygen barrier performance, good color tone after oxygen absorption, excellent strength and shape retention, and excellent moldability. Ta.

Claims (5)

A layer (A) containing a resin composition containing a polyester compound (a) and a transition metal catalyst;
A multilayer body comprising at least three layers, in which a layer (B) containing a thermoplastic resin (b) different from the polyester compound (a) is laminated on both sides of the layer (A), ) is the structure represented by the following formula (1) with respect to the total 100 mol% of the structural units represented by the following formula (1), formula (2) and formula (3) in the polyester compound (a). A multilayer body containing 30 to 55 mol% of a unit, 15 to 40 mol% of a structural unit represented by the following formula (2), and 20 to 40 mol% of a structural unit represented by the following formula (3).

(In the above formulas (1) to (3), n represents the amount of repeating unit, and the structural unit represented by the above formula (1), the structural unit shown by the above formula (2), and the above formula ( (corresponds to the composition ratio of the structural units expressed in 3)). The polyester compound (a) is represented by the formula (1) based on the total 100 mol% of the structural units represented by (i) the formula (1), the formula (2), and the formula (3). Contains 40 to 50 mol% of the structural unit, 20 to 35 mol% of the structural unit represented by the above formula (2), and 25 to 35 mol% of the structural unit represented by the above formula (3), and ( ii) The polyester compound (a) according to claim 1, wherein the total of the structural units represented by formulas (1) to (3) is 95 mol% or more with respect to 100 mol% of the total structural units of the polyester compound (a). multilayer body. The multilayer body according to claim 1, wherein the transition metal catalyst contains at least one transition metal selected from the group consisting of cobalt, nickel, and copper. The multilayer body according to claim 3, wherein the transition metal catalyst is contained in an amount of 0.5 to 10 ppm as a transition metal amount based on the mass of the polyester compound (a). A container comprising a multilayer body according to any one of claims 1 to 4.